Dehydration
Dehydration has been studied in 11 papers since 2017: 3 observational studies in people, 4 in animals, 4 reviews. The newest paper, Aug 22, 2025: “Association between dehydration and stroke, a retrospective cohort study of a large database”.
“It was associated with severe frailty (Odds Ratio (OR): 2.08 [95% confidence interval (CI): 1.11-3.90]; p = 0.02)”
None of its findings points the other way.
- 4 independent labs in 2 countries
- Funders: National Institute on Aging and others
- 1 of 9 findings with company ties
- Humans3
- Animals3
- Model organisms1
What did studies of Dehydration find?
4Studies of Dehydration measured 4 outcomes; the most studied are mortality (1 study), late-phase long-term potentiation (1) and basal synaptic responses (1).
Mortality
no changein humans1
1 study
Mortality
no changein humans1
Dehydration has no effect on mortality in humans (7% vs 5%, p = 0.91).
“Seven percent died when dehydrated compared to 5% in the non-dehydrated (p = 0.91).”
Humanssurgically treated for hip fracturen = 214
Clinical nutrition ESPEN
Late-phase long-term potentiation
downin mice1
1 study
Late-phase long-term potentiation
downin mice1
Dehydration impairs late-phase long-term potentiation in mice.
“induction of late-phase long-term potentiation was impaired.”
AnimalsDehydration adjusted to levels seen in mice 40 weeks and olderhippocampal slice
Age-dependent changes in brain hydration and synaptic plasticity
Brain research
Basal synaptic responses
upin mice1
1 study
Basal synaptic responses
upin mice1
Dehydration increases basal synaptic responses in mice.
“their basal synaptic responses were amplified at all stimulus voltages tested”
AnimalsDehydration adjusted to levels seen in mice 40 weeks and olderhippocampal slice
Age-dependent changes in brain hydration and synaptic plasticity
Brain research
Mood
downin humans1
1 study
Mood
downin humans1
Dehydration impairs mood in humans.
“whereas the mood was widely impaired”
Reviewmild dehydration
Effects of Dehydration on Brain Functioning: A Life-Span Perspective
Annals of nutrition & metabolism
What is Dehydration linked with?
7Studies link Dehydration with 7 measures, most often transient ischemic attack (1 study), ischemic stroke (1) and intracerebral hemorrhage (1).
Transient ischemic attack
upin humans1OR 2.88
1 study
Transient ischemic attack
upin humans1OR 2.88
Dehydration raises the risk of transient ischemic attack in humans (OR 2.88, 95% CI 2.74-3.28).
“and TIA (OR=2.88, 95% CI=2.74-3.28).”
Humans
Association between dehydration and stroke, a retrospective cohort study of a large database
Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association
Ischemic stroke
upin humans1OR 1.98
1 study
Ischemic stroke
upin humans1OR 1.98
Dehydration raises the risk of ischemic stroke in humans (OR 1.98, 95% CI 1.9-2.07).
“ischemic stroke (OR=1.98, 95% CI=1.9-2.07)”
Humans
Association between dehydration and stroke, a retrospective cohort study of a large database
Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association
Intracerebral hemorrhage
upin humans1OR 3.99
1 study
Intracerebral hemorrhage
upin humans1OR 3.99
Dehydration raises the risk of intracerebral hemorrhage in humans (OR 3.99, 95% CI 3.41-4.67).
“individuals with dehydration were 1.98-3.99 times more likely to develop stroke: intracerebral hemorrhage (OR=3.99, 95% CI=3.41-4.67)”
Humans
Association between dehydration and stroke, a retrospective cohort study of a large database
Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association
Neurodegenerative processes
upin rats1
1 study
Neurodegenerative processes
upin rats1
Dehydration is associated with neurodegenerative processes in rats.
“there is a specific enrichment of differentially expressed genes related to neurodegenerative processes in the aged cohort”
Animalshypothalamic supraoptic nucleus
npj aging
Length of hospital stay
upin humans1OR 2.28
1 study
Length of hospital stay
upin humans1OR 2.28
Dehydration is associated with length of hospital stay in humans (OR 2.28, 95% CI 1.29-4.04, p = 0.02).
“prolonged hospital stay (OR: 2.28 [95% CI: 1.29-4.04]; p = 0.02)”
Humanssurgically treated for hip fracturen = 214
Clinical nutrition ESPEN
Frailty
upin humans1OR 2.08
1 study
Frailty
upin humans1OR 2.08
Dehydration is associated with frailty in humans (OR 2.08, 95% CI 1.11-3.90, p = 0.02).
“It was associated with severe frailty (Odds Ratio (OR): 2.08 [95% confidence interval (CI): 1.11-3.90]; p = 0.02)”
Humanssurgically treated for hip fracturen = 214
Clinical nutrition ESPEN
Acute kidney injury
upin humans1
1 study
Acute kidney injury
upin humans1
Dehydration raises the risk of acute kidney injury in humans.
“dehydration generates vulnerability to diseases caused by tissue hypoperfusion, including acute kidney injury.”
Review
Haemodynamic frailty - A risk factor for acute kidney injury in the elderly
Ageing research reviews